I. Field of Invention
This invention is directed toward the field of hoses, more particularly hoses with coupling connectors at each end carrying pressurized fluids, and most particularly, to a novel garden hose having longitudinally extending internal ribs.
II. Discussion of the Prior Art
Flexible hose has been manufactured for many years, first out of natural rubber and more recently out of petrochemical derivatives such as synthetic rubber, thermo plastic rubbers or plastics. It has been known all along that kink resistance is related to diameter, wall thickness and the material's flexibility.
Kink resistance is inversely Proportional to diameter. The smaller the diameter the greater the flexibility, so the hose will readily bend, and not kink. It is directly related to wall thickness--a heavier wall will resist kinking. Most importantly, it is directly related to the flexibility (elongation) of the material. More flexible materials will bend rather than kink.
Burst strength is also directly related to diameter, wall thickness, flexibility, or, in this case, more correctly the tensile strength of the hose construction.
"Kinking" occurs when the hose is doubled over or twisted. With reference to a kinked hose 2 shown by FIGS. 2 and 13, that side which forms the inside surface 104 of the kink resists compression while that side forming the exterior surface 102 of the kink resists elongation. As a result, the walls of the hose more readily fold upon themselves. A consequence of kinking is that the fluid flow through the hose can be either severely restricted or stopped. Kinking is a nuisance, causing the user to waste time unkinking the hose.
Hoses, such as garden hoses or fuel delivery hoses, were initially made with thick walls to resist pressure However, this made the hose more cumbersome. Subsequently, fiber reinforcements became available. Rubber hoses were wrapped with woven tapes, another outer coating layer was added, and the whole assembly was vulcanized. The fiber reinforcement allowed the total wall thickness to be reduced.
Plastic hoses, derived from Petrochemicals, are typically extruded using soft vinyl thermoplastic. Extrusion manufacturing of hose is a continuous process. Soft vinyl thermoplastic is defined in the art by the degree of its hardness measured with a durometer. Typical durometer measurements for soft vinyl plastic range from 60 to 90 as measured by ASTM method D-2240.
By the time plastic hose came along the use of tapes had been replaced by "knitting" tire cord around the inner core of the hose, followed by the addition of an outer coating. This greatly added to burst strength and, due to the knitting of the fiber, the hose had some flexibility.
A more modern and faster production approach is "wrapped" fiber which is spirally wound around the inner core. Knitted reinforcement allows more elongation because of the inherent ability of the fibers to move and rearrange themselves. Spiral wound hose has straight lines of rigid fiber which restrict elongation thereby enhancing the tendency of that hose to kink.
Extreme kinking occurs when a new coiled garden hose is first used. One end is fastened to the faucet and the user walks with the other end away from the faucet without allowing the coiled hose to untwist. Kinking also occurs due to the routine movements of the user.
Rising prices and the scarcity of petrochemical raw materials has made the manufacture of thick walled hose uneconomical. Consequently hoses are being made with thinner walls, resulting in an increased tendency to kink.
When a thin wall modern hose does kink, water flow is shut off and the user must attempt to unkink it through manual manipulation such as swinging the hose to relax the kink or to walk back to the kink and manually straighten it. Some kinks require the user to walk all the way back to the faucet, shut off the flow thereby releasing the pressure, and unkink the hose. The user is further inconvenienced because he or she must walk back, turn on the water and then proceed to the far end to spray. An even more cumbersome problem arises when the user has already attached a large sprinkler device, such as an oscillating sprinkler to the end, and is forced to untwist the hose with this device attached.